(1 of )Bartlett Springs Road in Lake County snakes off to the left, as Forest road 15N06 climbs to the right, Friday, Sept. 14, 2018. Fire crews saved the homes as the Mendocino Complex Ranch fire roared through the Mendocino National Forest. (Kent Porter / The Press Democrat) 2018

(3 of )Middle Creek can be seen just outside of Upper Lake, Friday, Sept. 14, 2018. The trees were burned in the Mendocino Complex Ranch fire as it roared through the Mendocino National Forest. (Kent Porter / The Press Democrat) 2018

(4 of )An off-road trail zigs up a hillside, Friday, Sept. 14, 2018. The trees were burned in the Mendocino Complex Ranch fire as it roared through the Mendocino National Forest. (Kent Porter / The Press Democrat) 2018

(5 of )As far as the eye can see, hundreds of thousands of acres of the Snow Mountain Wilderness is devoid of vegetation, Friday, Sept. 14, 2018, due to the Mendocino Complex Ranch fire. In the photograph from left, background, is Hull Mountain, Snow Mountain, Snow Mountain East and Crockett Ridge in Lake County. (Kent Porter / The Press Democrat) 2018

(6 of )Caitlin Cornwall of the Sonoma Ecology Center surveys a grove of timber in Sugarloaf Ridge State Park, which was burned last October in the Nuns fire, on Sept. 13, 2018. (Kent Porter/The Press Democrat)

(8 of )Caitlin Cornwall of the Sonoma Ecology Center stands in a meadow of Sugarloaf Ridge State Park, which was burned last October in the Nuns fire, on Thursday, Sept. 13, 2018. (Kent Porter/The Press Democrat)

(9 of )Firefighters contained a brush fire near Redwood Valley along Highway 101, Friday, Sept. 14, 2018. The edge of the brush is red because of fire retardant dropped from an air tanker. (Kent Porter / The Press Democrat) 2018

(10 of )Cal Fire firefighters squelch a brush fire near Redwood Valley along Highway 101, Friday, Sept. 14, 2018. The brush is red because of fire retardant dropped from an air tanker. (Kent Porter / The Press Democrat) 2018

(11 of )An firefighter from the Chamberlain Creek inmate camp leaps over the edge of a brush fire along Highway 101, Friday, Sept. 14, 2018. The firefighter did not want to get stuck along a fence line between the flames. (Kent Porter / The Press Democrat) 2018

(12 of )Cal Fire firefighters are hit with water from the Boggs Helitack helicopter during a brush fire near Redwood Valley along Highway 101, Friday, Sept. 14, 2018. The brush is red because of fire retardant dropped from an air tanker. (Kent Porter / The Press Democrat) 2018

(13 of )Ally Fry of Cal Fire leads the way as she helps to squelch a brush fire near Redwood Valley along Highway 101, Friday, Sept. 14, 2018. (Kent Porter / The Press Democrat) 2018

(16 of )Middle Creek can be seen just outside of Upper Lake, Friday, Sept. 14, 2018. The trees were burned in the Mendocino Complex Ranch fire as it roared through the Mendocino National Forest. (Kent Porter / The Press Democrat) 2018

Striding through the brown, sun-dried grass on a slope at Sugarloaf Ridge State Park, Caitlin Cornwall stopped to touch a slender stalk of blue wild rye, crowned by a tasseled seed pod.

The 3,900-acre park in the Mayacamas Mountains near Kenwood was largely overrun by the Nuns fire in October, and the signs of recovery are abundant. Most of the live oak, bay and madrone trees survived; smaller Douglas firs perished and are being dismantled by beetles and woodpeckers.

The grasslands are generally healthier than they were before last fall’s blaze and could readily burn again, said Cornwall, a biologist with Sonoma Ecology Center, which has managed the park since 2012.

“This is all a fire-created natural community,” she said. The park burned in 1964, also by a fire named Nuns.

Indeed, fire shaped the drought-prone landscape for thousands of years, as Native Americans used it to maintain meadows and forests that provided deer, elk and acorns for food as well as grasses for basketry.

But now, climate change has thrown the symbiosis of humans, fire and the landscape into catastrophic disarray. Much of California is a yearround tinderbox, with fast-moving wildfires erupting so quickly this year that firefighters have rushed from one to the next, with the usual peak of the fire season still to come.

“It just takes one spark,” said Scott McLean, a deputy chief with Cal Fire, the state’s firefighting and forestry agency.

As heat-trapping gases continue to pour into the atmosphere and temperatures inch upward, drawing moisture from the soil and vegetation, the state’s vast landscape is growing increasingly volatile, costing lives and billions of dollars in fire damages.

Compounding the menace of climate change, experts say the wildfire situation is only going to get worse.

To say California is in a “new normal,” as Gov. Jerry Brown did last month, is misleading because it implies a steady condition going forward, said LeRoy Westerling, a management professor at UC Merced’s School of Engineering.

Instead, the state faces increasing peril from climate change for several decades to come, he said.

“What we’ve been observing on the ground keeps outpacing what we predict,” Westerling said. “The new abnormal is constant change.”

California’s Fourth Climate Change Assessment, released last month, said the Golden State is “one of the most ‘climate-challenged’ regions of North America,” with a historically variable climate that is now seeing “extreme conditions more frequent and severe.”

By century’s end, wildfires larger than 25,000 acres could become 50 percent more frequent if greenhouse gas emissions are not curtailed, the report said.

Cal Fire estimates wildland fires consumed 1.4 million acres last year, more than double the average of the previous decade.

As bad as 2017 was — with the North Bay wildfires killing 40 people and destroying more than 6,000 homes — fires this year have burned an estimated 1.3 million acres prior to October, the month when many of California’s all-time worst wildfires have raged.

Six of the state’s 20 most destructive fires — measured by structures destroyed — along with five of the 20 deadliest fires and three of the 20 largest, based on acreage, have ignited in 2017 and 2018.

The Mendocino Complex, a combination of two blazes started in late July and still smoldering in the southern part of the Mendocino National Forest, is now the largest ever at nearly 460,000 acres — 60 percent larger than the Thomas fire which raked Ventura and Santa Barbara counties in December.

The horrific Carr fire at Redding in July is on all three top-20 lists after killing seven people, destroying more than 1,600 structures and charring almost 230,000 acres.

“We haven’t gotten a break,” Cal Fire’s McLean said. State and local firefighters responded to 200 to 300 wildfires a week in July through August, and fought more than 1,000 fires one week in July, mostly small blazes and some over 300 acres.

“We’re just rolling from one (fire) to another,” he said.

The fire season started early in Northern California, with triple-digit heat and erratic winds in late May and early June, “drying out whatever moisture was in the plants,” McLean said.

Threatened residents are being evacuated more quickly, he said, as fires move rapidly and erratically.

The Delta fire, which broke out Sept. 5 along Interstate 5 in Shasta County, exploded to 15,000 acres in a matter of hours, a rate McLean characterized as stunning. At more than 60,000 acres Friday with about 3,300 personnel engaged, the blaze was 28 percent contained.

Under climate change, California’s already short rainy season is becoming further compressed into the winter months, said Daniel Swain, a UCLA climate scientist. The state is “burning the candle at both ends,” he said, with fires breaking out earlier in the spring, later in the fall and even in the winter months.

There’s also a subtlety to the trend many people may not notice, Swain said.

Nights have warmed faster than days during fire season, curbing the usual cool nights accompanied by humidity that prompts flames to “lay down,” giving firefighters some advantage in achieving containment, he said.

Swain and other experts cite two underlying factors contributing to the surge in fire danger.

Forests have grown thicker, the result of a 20th century adherence to the Smoky-the-Bear mantra of fire suppression, now widely regarded as a case of mismanagement that has overloaded the wildlands with fuel.

At the same time, California’s population has boomed, especially in the fire-prone areas where cities and suburbs merge with wildlands. There were more than 4.4 million California homes in these areas, known as the wildland-urban interface, in 2010, according to the U.S. Forest Service’s latest report.

The number has increased by more than 1 million homes since 1990 and is the highest in the nation, the report said.

In this setting, climate change amounts to a “threat multiplier,” Swain said, with more people in harm’s way as dense forests grow drier and weather grows hotter.

“It’s all moving in one direction and it’s getting worse,” he said.

Westerling, the UC Merced professor, said “we are watching the landscape get rearranged as climate change continues.”

“For everyone alive on the planet (now), we will never see a stable climate system again,” he said.

More than wild places are in jeopardy as wildfires burn hotter, longer and larger.

For everyone alive on the planet (now), we will never see a stable climate system again. — LeRoy Westerling, a management professor at UC Merced’s School of Engineering

The American Lung Association considers wildfire smoke “a serious and growing threat to public health,” said Will Barrett, the organization’s clean air advocacy director.

As the October wildfires raged, the Bay Area Air Quality Management District reported conditions comparable to Beijing, China and called it the worst air quality ever recorded in some parts of the Bay Area.

A study based on emergency room visits during California’s 2015 fire season found smoky air was associated with a 42 percent higher risk of heart attack compared to smoke-free air and a 22 percent higher relative risk of emergency visits for coronary artery disease.

The study was published in April by the Journal of the American Heart Association.

Wood smoke alone carries high levels of particle pollution that can be harmful to children and people with respiratory and cardiac conditions, Barrett said.

When homes and vehicles are consumed by fire, as they were by the thousands in Fountaingrove and Coffey Park in October, the smoke becomes a “toxic stew” of chemicals of all sorts, and little is known about them, he said.